function sse = compute_SSE(k, t_data, X_data)

% We assume that we know the initial value exactly
x0 = X_data(1,:)';

% Right-hand side of the ODE, i.e. f(x,k)
odefun = @(t,x) [k(1)*x(1) - k(2)*x(1)*x(2);
                            k(2)*x(1)*x(2) - x(2)];
                          
 % Solve the system at time points t_data
[~, X_out] = ode45(odefun, t_data, x0);

% Compute SSE
sse = ???

end